— 79 — 



Issmng from its foramen the nerve lies antero-dorsal to the rectus externus and postero-ventral 

 to the rectus superior, to wLicli latter muscle the siiperior division of the nerve immediately passes. 

 The inferior division of the nerve then comes into close contact with the ciliary ganglion, and there 

 immediately separates into two portions, the larger one of which is the branch for the recti inferior 

 and internus and the smaller one the branch for the obliquus inferior. The larger branch immediately 

 separates into its two parts, both of which run forward postero-ventral to the rectus superior, the 

 branch to the rectus inferior immediately entering its muscle, while the branch to the rectus internus 

 passes dorsal to the rectus inferior to reach its muscle. The ciliary ganglion lies upon the branch that 

 goes to the recti internus and inferior and is connected with it by fibers which represent the radix 

 brevis. The branch to the obliquus inferior turns downward and forward anterior to the rectus 

 externus but postero-ventral to the other three recti muscles, and so reaches its muscle. 



The branches of the oculomotorius and their relations to the recti muscles and the nervus 

 opticus, are thus exactly as in Scomber. 



In Lepidotrigla and Cottus the same arrangement is found; and Dactylopterus differs only 

 in that the oculomotorius separates into three parts while still inside the cranial cavity, one branch 

 destined to the rectus superior, one to the obliquus inferior, and the other to the recti inferior and 

 internus. In Cottus, there being no basisphenoid, the nerve, as it issues from the cranial cavity, 

 pierces the membrane that closes the orbital opening of the brain case, instead of there being enclosed 

 in bone. 



NERVUS TROCHLEARIS. 



The trochlearis has a central origin and intracerebral course similar to that given by Herrick 

 for this nerve in Menidia, and it issues from the brain along the ventral margin of the lobus opticus. 

 Running forward in the cranial cavity it does not come into close relations with any of the roots of 

 the trigeminus, or with nerves arising from those roots, differing, in ttis, from the nerve in Menidia. 

 This is also true of Lepidotrigla, Cottus and Dactylopterus. 



The nerve issues from the cranial cavity either along or through the edge of the alisphenoid, 

 and running dorsal to all the muscles of the eyeball enters and supplies the obliquus superior. 



NERVUS ABDUCENS. 



The abducens issues from the ventral surface of the meduUa oblongata slightly posterior to 

 the lobus inferior, and between or slightly anterior to the anterior roots of the nervi acustici of op- 

 posite sides. In all the young specimens of Scorpaena examined, it arose by a single root, but in the 

 adult specimen used for figure 28 it arose by two roots. In all of the specimens of Lepidotrigla 

 examined it arose by two roots, one slightly posterior to the other, as Stannius has said for Trigla 

 and Cottus. The one or two rootlets have their origin in a nucleus which lies, as in Menidia, at some 

 distance from the median line and at about one third the distance from the ventral surface of the 

 meduUa to the floor of the overlying ventricle. A strong tract of fibers crosses transversely between 

 the nuclei of opposite sides, but my sections did not give any indication either of the tract or the 

 bündle of fibers, described by Herrick in Menidia, that runs from the nucleus or root of the nerve 

 of either side dorsally into the fasciculus longitudinalis dorsalis. 



The abducens, having issued from the meduUa oblongata, runs forward beneath the hypo- 

 arium and, in the sections both of Scorpaena and Lepidotrigla, turns downward over the anterior 



